Armoured edge for building slabs



y 1968 G. J. VAN ELTEN 3,390,504

' B IL G 5 Filed June 29, 1965 2 Sheets-Sheet 1 July 2, 1968 e. .1. VANELTEN 3,390,504

ARMOURED EDGE FOR BUILDING SLABS Filed June 23, 1965 2 Sheets-Sheet 2United States Patent Claims. cl. 52-588) ABSTRACT OF THE DISCLOSURE Abuilding slab of wood wool and a mineral binder in which the edges ofthe slab are armoured with a U-shaped sheet metal edge, the centerportion of the U-shaped edge extending laterally on the edge from oneside of the slab to the other and a first and second flange integrallyjoined to the center portion of the U-shaped member, at the respectiveopposite ends of the center portion, one of the flanges having aninwardly bent end seated in and in engagement with a groove on one sideof the slab and the other flange having an inwardly bent portion forengagement into and seating in a groove extending longitudinally alongthe center portion adjacent to the second shaped portion on the centerportion extending longitudinally along the center portion adjacent tothe second flange which, when bent downwardly engages the bent end ofthe second flange, and seats the bent end in, the groove extendinglongitudinally along the opposite side of the slabs.

The present invention relates to a building slab, and more particularlyto a light weight building slab consisting of a long-fibrous insulativematerial such as wood wool and a mineral binding agent, the lateraledges of which are enclosed by metal channel-section members.

It is known in the art to armour building slabs which are used, forinstance, to line ceilings, floors, roofs, walls etc. along their edges.This protects their edges against damage and strengthens their staticcapacity. When the building slabs are installed in horizontal orinclined positions the armouring renders them more resistant againstbending strain so that the slabs may be installed in larger sizes, or,where they are self-supported, may take up heavier weights.

The armouring frequently consists of sheet metal strips of U-shapedcross section, the flanks of which form flanges engaging with the upperand lower surfaces of the building slab. In order to avoid loosening ofthe armouring from the building slab the two flanges are at theirlongitudinal edges internally bent and imbedded in grooves extendingparallel to the abutting faces of two adjoining slabs. The U-shapedarmouring strip is pushed or clamped into its grooves subsequent to themanufacture of the building slab. Due to the bending of greater buildingslabs during the pushing of the U-shaped armouring strip into thegrooves of the slab damage to the edges of the building slab is likelyto occur. Also slab parts of a slightly higher thickness are raisingdifficultiesfor the fastening of the U-shaped armouring strip to thebuilding slab.

Further, it has been known to increase the bending resistance of theU-shaped sheet metal strips serving as connecting elements of the slabsin that the flanges of the "ice sheet metal strips are folded in aplurality of layers. It is further known to bend the middle part of thearmouring strip parallel to the edges like the letter S. This S-shapedportion works as rib and groove with the next building slab together.

It is one object of the invention to provide for an increased length ofbuilding slabs to be armoured with an U-shaped armouring strip.

It is a further object of the invention to increase the bendingresistance of the building slab and thus to achieve a larger span widthof the slab.

To achieve this, a S-shaped bending portion of the armoured strip is putalong an edge of the building slab. Preferably the armoured strip showsbefore the clamping to the edge of the slab not yet a fully backwardbent S-shape. This open portion of the armoured strip is laid over thegroove extending parallel to the abutting face of the slab and then ispushed down with the internally bent parts of the flange into thegroove. This avoids the abovementioned disadvantages.

The S-shaped bending portion is situated near to one edge of thebuilding slab. This results in more iron cross section near the flangeof the armouring which increases the resistance moment of the armouring.

It is a further object of the invention, to provide for a layer ofwaterproof material upon the slab, which is clamped into the grooves bythe internally bent flanges. If the S-shaped bending portion is made ina way that the armouring strip runs straight ahead from the S-shapedbending portion to the flange of the strip a waterproof roofconstruction results.

In the following specification the invention will be further describedwith reference to the embodiments shown in the accompanying drawings, inwhich:

FIG. 1 is a cross section of the abutting point of two building slabs;

FIG. 2 is a cross section of a building slab and of an armouring stripin the position in which it is laterally applied against the slab priorto being pressed into the slab;

FIG. 3 is a cross section of a building slab with pressedin armouringstrips and a roof covering rigidly clamped by these strips;

FIG. 4 is a cross section of the abutting point of two inclined buildingslabs with reinforced marginal portions laid on beams of the roof;

FIG. 5 is a cross section of the abutting point of two building slabswith reinforced marginal portions and laid-in insulation strip;

FIG. 6 is a partial cross section of a pile of building slabs inaccordance with FIG. 5.

Wit-h reference to FIG. 1, the two building slabs 1 and 2, consisting ofwood wool and a binding agent, are at their abutting point provided witharmouring strips 3 and 4 respectively, which may be made, for instance,of galvanized steel plates and in their upper portions are provided, byS-type bending, with a rib 5, 6 and a groove 7, 8 each.

When the building slabs are laid, rib 5 engages with groove 7, and rib 6with groove 8. Above the S-type shaping, the two armouring strips 3 and4 are continued in the shape of flanges 18 which, owing to multiplefolding of the sheet metal, are formed of a plurality of layers. The

external edges 13 and 14 of flanges 18 are downwards bent by 90 andengage with grooves 9 and of the building slabs 1 and 2. At their lowerends, the armouring strips 3 and 4 are in a similar manner continued bya plurality of layers, which form flanges 17. The flanges 18 are mountedin excavations 11 and 12 at the upper Side of building slabs 1 and 2,these excavations being of such depth that the flanges 18 are inalignment with the surfaces and 16 of building slabs 1 and 2. The partof the material of the two armouring strips 3 and 4 contained in theribs 5 and 6 and in the grooves 7 and 8 is a good distance from the lineof bending neutrality of their center parts and therefore essentiallycontributes to the resistance moment of the armouring strips 3, 4.

In FIG. 2, the appliance of the armouring strips to the building slabsis shown, by way of example, with respect to slab 2. The flange 18 ofarmouring strip 4 is at first bent by an angle smaller than 180 so thatits outside edge does not yet engage with groove 10 of building slab 2.The armouring strip 4 may therefore be laterally laid against buildingslab 2 without any difficulty, and the outside edge 14', beingrectangularly bent in upward direction, may be pushed into thecorresponding groove 16' at the lower side of the building slab 2. Afterthe whole of armouring strip 4 has been caused to be adjacent to theslab, rib 5 is completely pressed together, for instance byhydraulically operated clamping jaws 19 or by press wheels, which causesthe inturned outside edge 14 of flange 18 to be resiliently pressed intogroove 10 of building slab 1. The pressing can be eflectuated withoutdifficulty by a suitable construction of the clamping jaws. As a result,the armouring strip 4 is given a springy and firm adhesion to the smoothedges of building slab 2, which is not in any way damaged by theapplication of the armouring strip 4, nor is the galvanized layer ofstrip 4 itself.

In the same manner, armouring strip 3 is connected with building slab 1so that, upon fastening of the two armouring strips 3, 4, the abuttingpoint of the slabs 1 and 2 receives its final shape shown in FIG. 1.

The building slab 21 shown in FIG. 3 is provided with a waterproofcovering 20, such as tar paper, a foil of plastic material or the like,which is laid on the surface of the slab before rib 5 is pressedtogether. When entering groove 10, the inturned outside edge 14 offlange 18 keeps covering tight and shortly before wedging it in thegroove gives it a span. This ensures even and stretched attachment ofcovering 20 to the surface 16 of the building slab and a waterproofconnection with it.

Building slabs provided with a waterproof coating are particularlyadvantageous for use as root linings, or the Waterproof coating may beused to protect building slabs which are sensitive to water, such asslabs made of gypsum or magnesite.

FIG. 4 shows the abutting point of two building slabs 1 and 2 which areused as roof coverings and laid on an inclined roof beam construction27. To increase their bending resistance, the marginal portions 23 ofslabs 1 and 2 are of thicker section than the center portions. Thegrooves and ribs are nearer the top than the ribs 5, 6 in the embodimentof FIGS. 1 to 3, by which arrangement the flanges 25 and 26 of armouringstrips 3 and 4 form a direct continuation of the ribs 28. This causesthe ribs 28 to be a greater distance from the line of bending neutralityof armouring strips 3 and 4 and thus increases the bend ing resistanceof armouring strips 3 and 4. The building slabs may, due to thisincrease in bending resistance, for instance, be laid self-supportingfrom one roof beam to another. So that the abutting point will beweatherproof when the slabs are used as roof coverings the flange 26,which bears over building slab 2, is provided with an inelined pa-rtallowing the rain water to run down flange 25, on to flange 26 and offover covering 20. As the upper surfaces of building slabs 1 and 2 are inalignment with each. other the rain water can be disposed of withouthindrance.

To reduce the heat conductivity of the metallic abutting point of thetwo armouring strips, the two building slabs of FIG. 5 are provided witha recess 22 which is shown by dotted lines. This causes an excavation atthe abutting point, into which a high quality heat insulation strip 21may be inserted in such a manner that its surface is in alignment withthe surfaces 15, 1 6 of the building slabs. At the same time, the lowersides of the slabs may be elevated up to the dotted line 24, which makesit possible to reduce the thickness of the center portion of thebuilding slab without prejudicing its bending resistance.

Apart from the savings in building materials enabled by thisconstruction, the construction according to the invention offers anadvantage in that the building slabs may, due to their marginal portions23, easily be piled up upon one another, as may be seen from FIG. 6. Inthe pile of slabs, the respective lower flange 17 of a building slabrests on flange 18 of the building slab underneath, whereas the upperand lower sides of the building slabs are spaced from one another andtherefore stay in full contact with the surrounding air.

For additional savings of time and labour on the building site, theoutside surfaces 15 and 16 may in the process of manufacture of theSlabs be provided with a cement layer offering protection against damageto the slabs by being trodden on, and also ensuring a smooth uppersurface, which is of advantage for application of tar paper etc.

The building slabs according to the invention are of such a high degreeof bending resistance that they are practically self-supporting overtheir whole length. They may therefore be laid directly from one roofbeam to another without requiring the intermediate supportingconstruction which has been needed so far. Other advantages of thebuilding slabs are their relatively light weight, their capability ofbeing dried while piled up and the protection against damage offered bythe armouring of their edges, which is particularly important ontransport.

What I claim is:

1. A building slab of mineralized wood wool having a U-shaped sheetmetal strip extending longitudinally along the edges of said slab andforming an armouring edge t-herealong, said U-shaped sheet metal striphaving a center portion extending laterally on said edges from one sideof said slab to the other side of said slab, a first flange portionjoined integrally to said center portion and extending longitudinallyalong one side of said slab adjacent the edge thereof, said first flangeportion having at its end an inwardly bent portion projecting and seatedin a groove extending longitudinally along said one side of said slab, asecond flange portion joined integrally to said center portion andextending longitudinally along the opposite side of said slab adjacentthe edge thereof, said second flange portion having at its end aninwardly bent portion for projecting into and seating in a grooveextending longitudinally along said opposite side of said slab, andmeans on said center portion and at the second flange end of said centerportion for bending and fixing said second flange into engagement withsaid opposite side of said slab and for moving said inwardly bentportion at the end of said second flange into and seating said inwardlybent portion in fixed position in said groove extending longitudinallyalong said opposite side of said slab.

2. A building slab is recited in claim 1 in which said bending means isan S-shaped portion of said center porton extending longitudinally alongsaid center portion adjacent to said second flange.

3. A building slab as recited in claim 2 in which said opposite side ofsaid slab is covered with a waterproof layer.

4. A building slab as recited in claim 3 in which said waterproof layeris held in engagement on said opposite side by said inwardly bentportion at the end of said second flange.

5. A building slab as recited in claim 4 in which said first and secondflange portion are formed by folding said sheet metal over itself atsaid flanges.

References Cited UNITED STATES PATENTS 6 2,180,317 11/1939 Davis 525882,950,786 8/1960 Markle 52588 2,771,165 11/1956 Bell 52627 FOREIGNPATENTS 715,770 1954 Great Britain.

FRANK L. ABBOTT, Primary Examiner.

ROBERT A. STENZEL, SAM D. BURKE, Assistant Examiners.

